﻿/**
 * Created by Wandergis on 2015/7/8.
 * 提供了百度坐标（BD09）、国测局坐标（火星坐标，GCJ02）、和WGS84坐标系之间的转换
 * Updated by FreeGIS on 2016/2/25.
 * 新增了百度经纬度与百度墨卡托互相转换方法
 */
//UMD魔法代码
// if the module has no dependencies, the above pattern can be simplified to
(function (root, factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module.
        define([], factory);
    } else if (typeof module === 'object' && module.exports) {
        // Node. Does not work with strict CommonJS, but
        // only CommonJS-like environments that support module.exports,
        // like Node.
        module.exports = factory();
    } else {
        // Browser globals (root is window)
        root.coordtransform = factory();
    }
}(this, function () {
    //定义一些常量
    var x_PI = 3.14159265358979324 * 3000.0 / 180.0;
    var PI = 3.1415926535897932384626;
    var a = 6378245.0;
    var ee = 0.00669342162296594323;
    /**
     * 百度坐标系 (BD-09) 与 火星坐标系 (GCJ-02)的转换
     * 即 百度 转 谷歌、高德
     * @param bd_lon
     * @param bd_lat
     * @returns {*[]}
     */
    var bd09togcj02 = function bd09togcj02(bd_lon, bd_lat) {
        var x_pi = 3.14159265358979324 * 3000.0 / 180.0;
        var x = bd_lon - 0.0065;
        var y = bd_lat - 0.006;
        var z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * x_pi);
        var theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * x_pi);
        var gg_lng = z * Math.cos(theta);
        var gg_lat = z * Math.sin(theta);
        return [gg_lng, gg_lat]
    };

    /**
     * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换
     * 即谷歌、高德 转 百度
     * @param lng
     * @param lat
     * @returns {*[]}
     */
    var gcj02tobd09 = function gcj02tobd09(lng, lat) {
        var z = Math.sqrt(lng * lng + lat * lat) + 0.00002 * Math.sin(lat * x_PI);
        var theta = Math.atan2(lat, lng) + 0.000003 * Math.cos(lng * x_PI);
        var bd_lng = z * Math.cos(theta) + 0.0065;
        var bd_lat = z * Math.sin(theta) + 0.006;
        return [bd_lng, bd_lat]
    };

    /**
     * WGS84转GCj02
     * @param lng
     * @param lat
     * @returns {*[]}
     */
    var wgs84togcj02 = function wgs84togcj02(lng, lat) {
        if (out_of_china(lng, lat)) {
            return [lng, lat]
        } else {
            var dlat = transformlat(lng - 105.0, lat - 35.0);
            var dlng = transformlng(lng - 105.0, lat - 35.0);
            var radlat = lat / 180.0 * PI;
            var magic = Math.sin(radlat);
            magic = 1 - ee * magic * magic;
            var sqrtmagic = Math.sqrt(magic);
            dlat = (dlat * 180.0) / ((a * (1 - ee)) / (magic * sqrtmagic) * PI);
            dlng = (dlng * 180.0) / (a / sqrtmagic * Math.cos(radlat) * PI);
            var mglat = lat + dlat;
            var mglng = lng + dlng;
            return [mglng, mglat]
        }
    };

    /**
     * GCJ02 转换为 WGS84
     * @param lng
     * @param lat
     * @returns {*[]}
     */
    var gcj02towgs84 = function gcj02towgs84(lng, lat) {
        if (out_of_china(lng, lat)) {
            return [lng, lat]
        } else {
            var dlat = transformlat(lng - 105.0, lat - 35.0);
            var dlng = transformlng(lng - 105.0, lat - 35.0);
            var radlat = lat / 180.0 * PI;
            var magic = Math.sin(radlat);
            magic = 1 - ee * magic * magic;
            var sqrtmagic = Math.sqrt(magic);
            dlat = (dlat * 180.0) / ((a * (1 - ee)) / (magic * sqrtmagic) * PI);
            dlng = (dlng * 180.0) / (a / sqrtmagic * Math.cos(radlat) * PI);
            mglat = lat + dlat;
            mglng = lng + dlng;
            return [lng * 2 - mglng, lat * 2 - mglat]
        }
    };

    var transformlat = function transformlat(lng, lat) {
        var ret = -100.0 + 2.0 * lng + 3.0 * lat + 0.2 * lat * lat + 0.1 * lng * lat + 0.2 * Math.sqrt(Math.abs(lng));
        ret += (20.0 * Math.sin(6.0 * lng * PI) + 20.0 * Math.sin(2.0 * lng * PI)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(lat * PI) + 40.0 * Math.sin(lat / 3.0 * PI)) * 2.0 / 3.0;
        ret += (160.0 * Math.sin(lat / 12.0 * PI) + 320 * Math.sin(lat * PI / 30.0)) * 2.0 / 3.0;
        return ret
    };

    var transformlng = function transformlng(lng, lat) {
        var ret = 300.0 + lng + 2.0 * lat + 0.1 * lng * lng + 0.1 * lng * lat + 0.1 * Math.sqrt(Math.abs(lng));
        ret += (20.0 * Math.sin(6.0 * lng * PI) + 20.0 * Math.sin(2.0 * lng * PI)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(lng * PI) + 40.0 * Math.sin(lng / 3.0 * PI)) * 2.0 / 3.0;
        ret += (150.0 * Math.sin(lng / 12.0 * PI) + 300.0 * Math.sin(lng / 30.0 * PI)) * 2.0 / 3.0;
        return ret
    };

    /**
     * 判断是否在国内，不在国内则不做偏移
     * @param lng
     * @param lat
     * @returns {boolean}
     */
    var out_of_china = function out_of_china(lng, lat) {
        return (lng < 72.004 || lng > 137.8347) || ((lat < 0.8293 || lat > 55.8271) || false);
    };

    //百度墨卡托转百度wgs84
    var EARTHRADIUS = 6370996.81;
    var MCBAND = [12890594.86, 8362377.87, 5591021, 3481989.83, 1678043.12, 0];
    var LLBAND = [75, 60, 45, 30, 15, 0];
    var MC2LL = [[1.410526172116255e-8, 0.00000898305509648872, -1.9939833816331, 200.9824383106796, -187.2403703815547, 91.6087516669843, -23.38765649603339, 2.57121317296198, -0.03801003308653, 17337981.2], [-7.435856389565537e-9, 0.000008983055097726239, -0.78625201886289, 96.32687599759846, -1.85204757529826, -59.36935905485877, 47.40033549296737, -16.50741931063887, 2.28786674699375, 10260144.86], [-3.030883460898826e-8, 0.00000898305509983578, 0.30071316287616, 59.74293618442277, 7.357984074871, -25.38371002664745, 13.45380521110908, -3.29883767235584, 0.32710905363475, 6856817.37], [-1.981981304930552e-8, 0.000008983055099779535, 0.03278182852591, 40.31678527705744, 0.65659298677277, -4.44255534477492, 0.85341911805263, 0.12923347998204, -0.04625736007561, 4482777.06], [3.09191371068437e-9, 0.000008983055096812155, 0.00006995724062, 23.10934304144901, -0.00023663490511, -0.6321817810242, -0.00663494467273, 0.03430082397953, -0.00466043876332, 2555164.4], [2.890871144776878e-9, 0.000008983055095805407, -3.068298e-8, 7.47137025468032, -0.00000353937994, -0.02145144861037, -0.00001234426596, 0.00010322952773, -0.00000323890364, 826088.5]];
    var LL2MC = [[-0.0015702102444, 111320.7020616939, 1704480524535203, -10338987376042340, 26112667856603880, -35149669176653700, 26595700718403920, -10725012454188240, 1800819912950474, 82.5], [0.0008277824516172526, 111320.7020463578, 647795574.6671607, -4082003173.641316, 10774905663.51142, -15171875531.51559, 12053065338.62167, -5124939663.577472, 913311935.9512032, 67.5], [0.00337398766765, 111320.7020202162, 4481351.045890365, -23393751.19931662, 79682215.47186455, -115964993.2797253, 97236711.15602145, -43661946.33752821, 8477230.501135234, 52.5], [0.00220636496208, 111320.7020209128, 51751.86112841131, 3796837.749470245, 992013.7397791013, -1221952.21711287, 1340652.697009075, -620943.6990984312, 144416.9293806241, 37.5], [-0.0003441963504368392, 111320.7020576856, 278.2353980772752, 2485758.690035394, 6070.750963243378, 54821.18345352118, 9540.606633304236, -2710.55326746645, 1405.483844121726, 22.5], [-0.0003218135878613132, 111320.7020701615, 0.00369383431289, 823725.6402795718, 0.46104986909093, 2351.343141331292, 1.58060784298199, 8.77738589078284, 0.37238884252424, 7.45]];

    /**
    * 百度墨卡托转百度经纬度
    * @param lng
    * @param lat
    * @returns {*[]}
    */
    var bd_mkt2bd_wgs = function bd_mkt2bd_wgs(lng, lat) {
        var cF = null;
        lng = Math.abs(lng);
        lat = Math.abs(lat);
        for (var cE = 0; cE < MCBAND.length; cE++) {
            if (lat >= MCBAND[cE]) {
                cF = MC2LL[cE];
                break;
            }
        }
        var lng = cF[0] + cF[1] * Math.abs(lng);
        var cC = Math.abs(lat) / cF[9];
        var lat = cF[2] + cF[3] * cC + cF[4] * cC * cC + cF[5] * cC * cC * cC + cF[6] * cC * cC * cC * cC + cF[7] * cC * cC * cC * cC * cC + cF[8] * cC * cC * cC * cC * cC * cC;
        lng *= (lng < 0 ? -1 : 1);
        lat *= (lat < 0 ? -1 : 1);
        return [lng, lat];
    };

    /**
    * 百度经纬度转百度墨卡托
    * @param lng
    * @param lat
    * @returns {*[]}
    */
    var bd_wgs2bd_mkt = function bd_wgs2bd_mkt(lng, lat) {
        var cF = null;
        lng = getLoop(lng, -180, 180);
        lat = getRange(lat, -74, 74);
        for (var i = 0; i < LLBAND.length; i++) {
            if (lat >= LLBAND[i]) {
                cF = LL2MC[i];
                break;
            }
        }
        if (cF != null) {
            for (var i = LLBAND.length - 1; i >= 0; i--) {
                if (lat <= -LLBAND[i]) {
                    cF = LL2MC[i];
                    break;
                }
            }
        }
        var lng = cF[0] + cF[1] * Math.abs(lng);
        var cC = Math.abs(lat) / cF[9];
        var lat = cF[2] + cF[3] * cC + cF[4] * cC * cC + cF[5] * cC * cC * cC + cF[6] * cC * cC * cC * cC + cF[7] * cC * cC * cC * cC * cC + cF[8] * cC * cC * cC * cC * cC * cC;
        lng *= (lng < 0 ? -1 : 1);
        lat *= (lat < 0 ? -1 : 1);
        return [lng, lat];
    }

    var getLoop = function getLoop(lng, min, max) {
        while (lng > max) {
            lng -= max - min;
        }
        while (lng < min) {
            lng += max - min;
        }
        return lng;
    }

    var getRange = function getRange(lat, min, max) {
        if (min != null) {
            lat = Math.max(lat, min);
        }
        if (max != null) {
            lat = Math.min(lat, max);
        }
        return lat;
    }

    return {
        bd09togcj02: bd09togcj02,
        gcj02tobd09: gcj02tobd09,
        wgs84togcj02: wgs84togcj02,
        gcj02towgs84: gcj02towgs84,
        bd_mkt2bd_wgs: bd_mkt2bd_wgs,
        bd_wgs2bd_mkt: bd_wgs2bd_mkt
    }
}));